/*
 * $Header:
 * /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons
 * //httpclient/src/java/org/apache/commons/httpclient/util/URIUtil.java,v 1.27
 * 2004/05/05 20:34:01 olegk Exp $ $Revision: 507321 $ $Date: 2007-02-14
 * 01:10:51 +0100 (Wed, 14 Feb 2007) $
 *
 * ====================================================================
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with this
 * work for additional information regarding copyright ownership. The ASF
 * licenses this file to You under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many individuals on
 * behalf of the Apache Software Foundation. For more information on the Apache
 * Software Foundation, please see <http://www.apache.org/>.
 */

package com.microsoft.tfs.core.httpclient.util;

import java.util.BitSet;

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.net.URLCodec;

import com.microsoft.tfs.core.httpclient.URI;
import com.microsoft.tfs.core.httpclient.URIException;

/**
 * The URI escape and character encoding and decoding utility. It's compatible
 * with {@link com.microsoft.tfs.core.httpclient.HttpURL} rather than
 * {@link com.microsoft.tfs.core.httpclient.URI}.
 *
 * @author <a href="mailto:jericho@apache.org">Sung-Gu</a>
 * @version $Revision: 507321 $ $Date: 2002/03/14 15:14:01
 */
public class URIUtil {

    // ----------------------------------------------------- Instance variables

    protected static final BitSet empty = new BitSet(1);

    // ---------------------------------------------------------- URI utilities

    /**
     * Get the basename of an URI. It's possibly an empty string.
     *
     * @param uri
     *        a string regarded an URI
     * @return the basename string; an empty string if the path ends with slash
     */
    public static String getName(final String uri) {
        if (uri == null || uri.length() == 0) {
            return uri;
        }
        final String path = URIUtil.getPath(uri);
        final int at = path.lastIndexOf("/");
        final int to = path.length();
        return (at >= 0) ? path.substring(at + 1, to) : path;
    }

    /**
     * Get the query of an URI.
     *
     * @param uri
     *        a string regarded an URI
     * @return the query string; <code>null</code> if empty or undefined
     */
    public static String getQuery(final String uri) {
        if (uri == null || uri.length() == 0) {
            return null;
        }
        // consider of net_path
        int at = uri.indexOf("//");
        int from = uri.indexOf("/", at >= 0 ? (uri.lastIndexOf("/", at - 1) >= 0 ? 0 : at + 2) : 0);
        // the authority part of URI ignored
        int to = uri.length();
        // reuse the at and from variables to consider the query
        at = uri.indexOf("?", from);
        if (at >= 0) {
            from = at + 1;
        } else {
            return null;
        }
        // check the fragment
        if (uri.lastIndexOf("#") > from) {
            to = uri.lastIndexOf("#");
        }
        // get the path and query.
        return (from < 0 || from == to) ? null : uri.substring(from, to);
    }

    /**
     * Get the path of an URI.
     *
     * @param uri
     *        a string regarded an URI
     * @return the path string
     */
    public static String getPath(final String uri) {
        if (uri == null) {
            return null;
        }
        // consider of net_path
        final int at = uri.indexOf("//");
        final int from = uri.indexOf("/", at >= 0 ? (uri.lastIndexOf("/", at - 1) >= 0 ? 0 : at + 2) : 0);
        // the authority part of URI ignored
        int to = uri.length();
        // check the query
        if (uri.indexOf('?', from) != -1) {
            to = uri.indexOf('?', from);
        }
        // check the fragment
        if (uri.lastIndexOf("#") > from && uri.lastIndexOf("#") < to) {
            to = uri.lastIndexOf("#");
        }
        // get only the path.
        return (from < 0) ? (at >= 0 ? "/" : uri) : uri.substring(from, to);
    }

    /**
     * Get the path and query of an URI.
     *
     * @param uri
     *        a string regarded an URI
     * @return the path and query string
     */
    public static String getPathQuery(final String uri) {
        if (uri == null) {
            return null;
        }
        // consider of net_path
        final int at = uri.indexOf("//");
        final int from = uri.indexOf("/", at >= 0 ? (uri.lastIndexOf("/", at - 1) >= 0 ? 0 : at + 2) : 0);
        // the authority part of URI ignored
        int to = uri.length();
        // Ignore the '?' mark so to ignore the query.
        // check the fragment
        if (uri.lastIndexOf("#") > from) {
            to = uri.lastIndexOf("#");
        }
        // get the path and query.
        return (from < 0) ? (at >= 0 ? "/" : uri) : uri.substring(from, to);
    }

    /**
     * Get the path of an URI and its rest part.
     *
     * @param uri
     *        a string regarded an URI
     * @return the string from the path part
     */
    public static String getFromPath(final String uri) {
        if (uri == null) {
            return null;
        }
        // consider of net_path
        final int at = uri.indexOf("//");
        final int from = uri.indexOf("/", at >= 0 ? (uri.lastIndexOf("/", at - 1) >= 0 ? 0 : at + 2) : 0);
        // get the path and its rest.
        return (from < 0) ? (at >= 0 ? "/" : uri) : uri.substring(from);
    }

    // ----------------------------------------------------- Encoding utilities

    /**
     * Get the all escaped and encoded string with the default protocl charset.
     * It's the same function to use <code>encode(String unescaped, Bitset
     * empty, URI.getDefaultProtocolCharset())</code>.
     *
     * @param unescaped
     *        an unescaped string
     * @return the escaped string
     *
     * @throws URIException
     *         if the default protocol charset is not supported
     *
     * @see URI#getDefaultProtocolCharset
     * @see #encode
     */
    public static String encodeAll(final String unescaped) throws URIException {
        return encodeAll(unescaped, URI.getDefaultProtocolCharset());
    }

    /**
     * Get the all escaped and encoded string with a given charset. It's the
     * same function to use <code>encode(String unescaped, Bitset
     * empty, String charset)</code>.
     *
     * @param unescaped
     *        an unescaped string
     * @param charset
     *        the charset
     * @return the escaped string
     *
     * @throws URIException
     *         if the charset is not supported
     *
     * @see #encode
     */
    public static String encodeAll(final String unescaped, final String charset) throws URIException {

        return encode(unescaped, empty, charset);
    }

    /**
     * Escape and encode a string regarded as within the authority component of
     * an URI with the default protocol charset. Within the authority component,
     * the characters ";", ":", "@", "?", and "/" are reserved.
     *
     * @param unescaped
     *        an unescaped string
     * @return the escaped string
     *
     * @throws URIException
     *         if the default protocol charset is not supported
     *
     * @see URI#getDefaultProtocolCharset
     * @see #encode
     */
    public static String encodeWithinAuthority(final String unescaped) throws URIException {

        return encodeWithinAuthority(unescaped, URI.getDefaultProtocolCharset());
    }

    /**
     * Escape and encode a string regarded as within the authority component of
     * an URI with a given charset. Within the authority component, the
     * characters ";", ":", "@", "?", and "/" are reserved.
     *
     * @param unescaped
     *        an unescaped string
     * @param charset
     *        the charset
     * @return the escaped string
     *
     * @throws URIException
     *         if the charset is not supported
     *
     * @see #encode
     */
    public static String encodeWithinAuthority(final String unescaped, final String charset) throws URIException {

        return encode(unescaped, URI.allowed_within_authority, charset);
    }

    /**
     * Escape and encode a string regarded as the path and query components of
     * an URI with the default protocol charset.
     *
     * @param unescaped
     *        an unescaped string
     * @return the escaped string
     *
     * @throws URIException
     *         if the default protocol charset is not supported
     *
     * @see URI#getDefaultProtocolCharset
     * @see #encode
     */
    public static String encodePathQuery(final String unescaped) throws URIException {
        return encodePathQuery(unescaped, URI.getDefaultProtocolCharset());
    }

    /**
     * Escape and encode a string regarded as the path and query components of
     * an URI with a given charset.
     *
     * @param unescaped
     *        an unescaped string
     * @param charset
     *        the charset
     * @return the escaped string
     *
     * @throws URIException
     *         if the charset is not supported
     *
     * @see #encode
     */
    public static String encodePathQuery(final String unescaped, final String charset) throws URIException {

        final int at = unescaped.indexOf('?');
        if (at < 0) {
            return encode(unescaped, URI.allowed_abs_path, charset);
        }
        // else
        return encode(unescaped.substring(0, at), URI.allowed_abs_path, charset)
            + '?'
            + encode(unescaped.substring(at + 1), URI.allowed_query, charset);
    }

    /**
     * Escape and encode a string regarded as within the path component of an
     * URI with the default protocol charset. The path may consist of a sequence
     * of path segments separated by a single slash "/" character. Within a path
     * segment, the characters "/", ";", "=", and "?" are reserved.
     *
     * @param unescaped
     *        an unescaped string
     * @return the escaped string
     *
     * @throws URIException
     *         if the default protocol charset is not supported
     *
     * @see URI#getDefaultProtocolCharset
     * @see #encode
     */
    public static String encodeWithinPath(final String unescaped) throws URIException {

        return encodeWithinPath(unescaped, URI.getDefaultProtocolCharset());
    }

    /**
     * Escape and encode a string regarded as within the path component of an
     * URI with a given charset. The path may consist of a sequence of path
     * segments separated by a single slash "/" character. Within a path
     * segment, the characters "/", ";", "=", and "?" are reserved.
     *
     * @param unescaped
     *        an unescaped string
     * @param charset
     *        the charset
     * @return the escaped string
     *
     * @throws URIException
     *         if the charset is not supported
     *
     * @see #encode
     */
    public static String encodeWithinPath(final String unescaped, final String charset) throws URIException {

        return encode(unescaped, URI.allowed_within_path, charset);
    }

    /**
     * Escape and encode a string regarded as the path component of an URI with
     * the default protocol charset.
     *
     * @param unescaped
     *        an unescaped string
     * @return the escaped string
     *
     * @throws URIException
     *         if the default protocol charset is not supported
     *
     * @see URI#getDefaultProtocolCharset
     * @see #encode
     */
    public static String encodePath(final String unescaped) throws URIException {
        return encodePath(unescaped, URI.getDefaultProtocolCharset());
    }

    /**
     * Escape and encode a string regarded as the path component of an URI with
     * a given charset.
     *
     * @param unescaped
     *        an unescaped string
     * @param charset
     *        the charset
     * @return the escaped string
     *
     * @throws URIException
     *         if the charset is not supported
     *
     * @see #encode
     */
    public static String encodePath(final String unescaped, final String charset) throws URIException {

        return encode(unescaped, URI.allowed_abs_path, charset);
    }

    /**
     * Escape and encode a string regarded as within the query component of an
     * URI with the default protocol charset. When a query comprise the name and
     * value pairs, it is used in order to encode each name and value string.
     * The reserved special characters within a query component are being
     * included in encoding the query.
     *
     * @param unescaped
     *        an unescaped string
     * @return the escaped string
     *
     * @throws URIException
     *         if the default protocol charset is not supported
     *
     * @see URI#getDefaultProtocolCharset
     * @see #encode
     */
    public static String encodeWithinQuery(final String unescaped) throws URIException {

        return encodeWithinQuery(unescaped, URI.getDefaultProtocolCharset());
    }

    /**
     * Escape and encode a string regarded as within the query component of an
     * URI with a given charset. When a query comprise the name and value pairs,
     * it is used in order to encode each name and value string. The reserved
     * special characters within a query component are being included in
     * encoding the query.
     *
     * @param unescaped
     *        an unescaped string
     * @param charset
     *        the charset
     * @return the escaped string
     *
     * @throws URIException
     *         if the charset is not supported
     *
     * @see #encode
     */
    public static String encodeWithinQuery(final String unescaped, final String charset) throws URIException {

        return encode(unescaped, URI.allowed_within_query, charset);
    }

    /**
     * Escape and encode a string regarded as the query component of an URI with
     * the default protocol charset. When a query string is not misunderstood
     * the reserved special characters ("&amp;", "=", "+", ",", and "$") within
     * a query component, this method is recommended to use in encoding the
     * whole query.
     *
     * @param unescaped
     *        an unescaped string
     * @return the escaped string
     *
     * @throws URIException
     *         if the default protocol charset is not supported
     *
     * @see URI#getDefaultProtocolCharset
     * @see #encode
     */
    public static String encodeQuery(final String unescaped) throws URIException {
        return encodeQuery(unescaped, URI.getDefaultProtocolCharset());
    }

    /**
     * Escape and encode a string regarded as the query component of an URI with
     * a given charset. When a query string is not misunderstood the reserved
     * special characters ("&amp;", "=", "+", ",", and "$") within a query
     * component, this method is recommended to use in encoding the whole query.
     *
     * @param unescaped
     *        an unescaped string
     * @param charset
     *        the charset
     * @return the escaped string
     *
     * @throws URIException
     *         if the charset is not supported
     *
     * @see #encode
     */
    public static String encodeQuery(final String unescaped, final String charset) throws URIException {

        return encode(unescaped, URI.allowed_query, charset);
    }

    /**
     * Escape and encode a given string with allowed characters not to be
     * escaped and the default protocol charset.
     *
     * @param unescaped
     *        a string
     * @param allowed
     *        allowed characters not to be escaped
     * @return the escaped string
     *
     * @throws URIException
     *         if the default protocol charset is not supported
     *
     * @see URI#getDefaultProtocolCharset
     */
    public static String encode(final String unescaped, final BitSet allowed) throws URIException {

        return encode(unescaped, allowed, URI.getDefaultProtocolCharset());
    }

    /**
     * Escape and encode a given string with allowed characters not to be
     * escaped and a given charset.
     *
     * @param unescaped
     *        a string
     * @param allowed
     *        allowed characters not to be escaped
     * @param charset
     *        the charset
     * @return the escaped string
     */
    public static String encode(final String unescaped, final BitSet allowed, final String charset)
        throws URIException {
        final byte[] rawdata = URLCodec.encodeUrl(allowed, EncodingUtil.getBytes(unescaped, charset));
        return EncodingUtil.getAsciiString(rawdata);
    }

    /**
     * Unescape and decode a given string regarded as an escaped string with the
     * default protocol charset.
     *
     * @param escaped
     *        a string
     * @return the unescaped string
     *
     * @throws URIException
     *         if the string cannot be decoded (invalid)
     *
     * @see URI#getDefaultProtocolCharset
     */
    public static String decode(final String escaped) throws URIException {
        try {
            final byte[] rawdata = URLCodec.decodeUrl(EncodingUtil.getAsciiBytes(escaped));
            return EncodingUtil.getString(rawdata, URI.getDefaultProtocolCharset());
        } catch (final DecoderException e) {
            throw new URIException(e.getMessage());
        }
    }

    /**
     * Unescape and decode a given string regarded as an escaped string.
     *
     * @param escaped
     *        a string
     * @param charset
     *        the charset
     * @return the unescaped string
     *
     * @throws URIException
     *         if the charset is not supported
     *
     * @see Coder#decode
     */
    public static String decode(final String escaped, final String charset) throws URIException {

        return Coder.decode(escaped.toCharArray(), charset);
    }

    // ---------------------------------------------------------- Inner classes

    /**
     * The basic and internal utility for URI escape and character encoding and
     * decoding.
     *
     * @deprecated use org.apache.commons.codec.net.URLCodec
     */
    @Deprecated
    protected static class Coder extends URI {

        /**
         * Escape and encode a given string with allowed characters not to be
         * escaped.
         *
         * @param unescapedComponent
         *        an unescaped component
         * @param allowed
         *        allowed characters not to be escaped
         * @param charset
         *        the charset to encode
         * @return the escaped and encoded string
         *
         * @throws URIException
         *         if the charset is not supported
         *
         * @deprecated use org.apache.commons.codec.net.URLCodec
         */
        @Deprecated
        public static char[] encode(final String unescapedComponent, final BitSet allowed, final String charset)
            throws URIException {

            return URI.encode(unescapedComponent, allowed, charset);
        }

        /**
         * Unescape and decode a given string.
         *
         * @param escapedComponent
         *        an being-unescaped component
         * @param charset
         *        the charset to decode
         * @return the escaped and encoded string
         *
         * @throws URIException
         *         if the charset is not supported
         *
         * @deprecated use org.apache.commons.codec.net.URLCodec
         */
        @Deprecated
        public static String decode(final char[] escapedComponent, final String charset) throws URIException {

            return URI.decode(escapedComponent, charset);
        }

        /**
         * Verify whether a given string is escaped or not
         *
         * @param original
         *        given characters
         * @return true if the given character array is 7 bit ASCII-compatible.
         */
        public static boolean verifyEscaped(final char[] original) {
            for (int i = 0; i < original.length; i++) {
                final int c = original[i];
                if (c > 128) {
                    return false;
                } else if (c == '%') {
                    if (Character.digit(original[++i], 16) == -1 || Character.digit(original[++i], 16) == -1) {
                        return false;
                    }
                }
            }
            return true;
        }

        /**
         * Replace from a given character to given character in an array order
         * for a given string.
         *
         * @param original
         *        a given string
         * @param from
         *        a replacing character array
         * @param to
         *        a replaced character array
         * @return the replaced string
         */
        public static String replace(String original, final char[] from, final char[] to) {
            for (int i = from.length; i > 0; --i) {
                original = replace(original, from[i], to[i]);
            }
            return original;
        }

        /**
         * Replace from a given character to given character for a given string.
         *
         * @param original
         *        a given string
         * @param from
         *        a replacing character array
         * @param to
         *        a replaced character array
         * @return the replaced string
         */
        public static String replace(final String original, final char from, final char to) {
            final StringBuffer result = new StringBuffer(original.length());
            int at, saved = 0;
            do {
                at = original.indexOf(from);
                if (at >= 0) {
                    result.append(original.substring(0, at));
                    result.append(to);
                } else {
                    result.append(original.substring(saved));
                }
                saved = at;
            } while (at >= 0);
            return result.toString();
        }
    }

}
